Analysis of prostatic fluid provides a unique opportunity for studying metabolic changes within the prostate gland. The overall objective of the project is to identify changes in the prostatic fluid composition that are associated with the presence of carcinoma of the prostate. Recognition of the changes has a significant potential to assist in achieving the following goals: 1) Provide an important additional technique for identification of patients with carcinoma of the prostate or those at high risk of developing prostatic cancer. 2) Provide information that may lead to the development of other procedures that will assist in identifying this group of patients. 3) Provide a possible means to identify variations in biological activity of prostatic carcinoma. Our previous studies, utilizing LDH isoenzymes as a biological marker in the prostatic fluid, have demonstrated characteristic ratios of LDH-5/LDH-1 in prostatic fluid specimens from individuals with normal prostate, benign hyperplasia and prostatic cancer. However, prostatic fluid collected from patients with prostatic inflammation (as indicated by the presence of 10 or more white blood cells in the prostatic fluid under the high power microscopic field) showed a wide range of LDH-5/1 ratio in the fluid which overlapped considerably with that of prostatic cancer cases. Our recent attempts exploring additional markers in the prostatic fluid appeared encouraging. Preliminary data obtained from analyzing C3, C4 complement components and transferrin indicated that elevated levels of these markers were associated with prostatic cancer but not with normal prostate, benign hyperplasia and prostatic inflammation. We propose: 1) To analyze C3 complement and transferrin in conjunction with LDH isoenzymes in the prostatic fluid to confirm our preliminary study in an attempt to increase our ability to identify men with carcinoma of the prostate. 2) to perform a retrospective study to assess the correlation (or lack of it) between the above markers and the stage, grade and biological behavior of the prostatic carcinoma.